About to receive the Royal Society’s Copley Medal, Britain’s highest scientific award, Stephen Hawking told a BBC radio audience that if the human race were to survive, it would be necessary to go to another star. Here’s a quote from a story on this in the Daily Mail:

“The long-term survival of the human race is at risk as long as it is confined to a single planet… Sooner or later, disasters such as an asteroid collision or nuclear war could wipe us all out. But once we spread out into space and establish independent colonies, our future should be safe. There isn’t anywhere like the Earth in the solar system, so we would have to go to another star.”

Hawking acknowledges the immense problems, telling his interviewer that chemical rockets like the Saturn V used on Apollo would require tens of thousands of years to reach Alpha Centauri. And while he has an admiration for Star Trek‘s warp drive (and is quite a fan of the series, as Trekkies know), Hawking pins his hopes on antimatter, forseeing future technologies that might reach speeds equal to a high percentage of the speed of light.

Alpha Centauri in six years? Not bad, and if you can get to .86 c, you’ve created time dilation that reduces the travel time for those aboard to three years. That’s just the figure used by physicist and science fiction writer Gerald Nordley when I talked to him in 2004 about a viable manned star mission. Nordley’s view: The first humans will reach Alpha Centauri in about the same time it took Magellan’s crew to circle the Earth — three years. That’s three years shipboard time, six as seen by observers on Earth, and puts Nordley and Hawking very much on the same page.

That the odds on survival here on Earth may be diminishing doesn’t seem to be just Hawking’s view. Consider James Lovelock, also quoted in a Daily Mail story, who points to climate change as the culprit in the coming reduction of Earth’s population from 6.5 billion to 500 million. Lovelock, you may remember, first proposed the Gaia Hypothesis, the notion that the Earth is a balanced system whose parts, like a human body, all mesh to create conditions possible for life.

Speaking to the Institution of Chemical Engineers in London, Lovelock had this to say:

“There is very good evidence of what happened 55 million years ago when as much carbon dioxide was put into the atmosphere by geology as is being done by us now. Temperatures zoomed up by 8 degrees and stayed there for 200,000 years then came back to normal.”

Go back 55 million years and you’re in the tropical era known as the Eocene. If we are about to reproduce Eocene-like conditions, is there anything we can do about it? Lovelock thinks that attempts to remedy ‘global heating,’ as he calls it, are simply buying us time, but doubts the entire human race will be destroyed, with survivors in arctic refuges possibly undergoing new evolution. That’s an outcome quite similar to what happens in Ronald Wright’s unsettling novel A Scientific Romance. Whether it’s true or not, I’m with Hawking in hoping for the interstellar propulsion breakthrough that can offer us a refuge just in case.